First Detector Training EMERALD ASH BORER MONITORING & MANAGEMENT

Transcription

1 First Detector Training EMERALD ASH BORER MONITORING & MANAGEMENT

2 EAB Module 2

3 Module Objectives The purpose of this module is to review the biology and ecology of an exotic, invasive tree pest called emerald ash borer (EAB). Upon completing this module, you should be able to: Describe the taxonomy of EAB Identify the physical characteristics of EAB Explain the life cycle of EAB Name the plant hosts of EAB Summarize the variety of EAB natural enemies Debbie Miller, USDA Forest Service, Bugwood.org

4 Taxonomy and Description Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Buprestidae Genus: Agrilus Species: planipennis Binomial name: Agrilus planipennis (Fairmaire) Adults are: Iridescent green, wood-boring beetle About 1/2 long and 1/6 wide Flat-headed, creating D-shaped holes in bark when emerging from pupation Kent Loeffler, Cornell University

5 Life Cycle EAB adults are active from late May to mid-august. They live for about 3-4 weeks and feed on ash foliage. After mating, females lay eggs, one at a time, on the bark of ash trees. They prefer to lay eggs where there are cracks so the hatching larvae can squeeze into cracks and bore into the bark. EAB density is lower in the smoothbarked upper crown areas and smaller diameter white ash. David Cappaert, Michigan State University, Bugwood.org EAB eggs are about the size of a pinhead and hatch 7-10 days after being deposited. Eggs change color from creamy white to brown. Debbie Miller, USDA FS, Bugwood.org

6 Life Cycle June/July Oviposition Summer/Fall Larval growth May/June Adult Emergence Ovary maturation Winter Pre-pupae Early spring Pupation EAB eggs, Debbie Miller, USDA FS, Bugwood.org; larva, prepupa and pupa, David Cappaert, Michigan State University, Bugwood.org; EAB exit holes, Daniel Herms, the Ohio State University, Bugwood.org; EAB adult, David Cappaert, Michigan State University, Bugwood.org

7 White ash bark anatomy Mark Whitmore, Cornell University

8 Life Cycle After hatching, EAB larvae bore into the bark and feed on the tree s phloem and cambium, eventually growing up to 2 cm in length. The larval stage kills the ash tree because its feeding disrupts the tree s flow of food and nutrients. Tree death occurs within 2 or more years depending on pest pressure. David Cappaert, Michigan State University, Bugwood.org EAB larvae overwinter as pre-pupae in the bark or within the outer ½ inch of the wood. They pupate the following spring. In colder regions or in earlier stages of infestation, the life cycle may take two years to complete. Mark Whitmore, Cornell University

9 Where to find EAB in ash Mark Whitmore, Cornell University

10 Life Cycle The pupal stage begins in spring and lasts about 28 days. Initial EAB adult emergence typically coincides with blooming of black locust (Robinia peseudoacacia), or about 450 GDD base 50 degrees F. Peak emergence is at about 900 GDD, usually in early June. Because their heads are flat on top, EAB adults create D- shaped holes in the bark as they emerge from pupation. These holes are about 1/8 wide. David Cappaert, Michigan State University, Bugwood.org Daniel Herms, the Ohio State University, Bugwood.org

11 Review How do EAB kill an ash tree? Answer When do adult EAB emerge? Answer Debbie Miller, USDA FS, Bugwood.org

12 Taxonomy and Life Cycle Summary Egg Stage Duration Comments 7 10 days On and underneath bark; size of pinhead Larva Pupa Adult Typically 9 10 months 28 days 3-4 weeks Underneath bark; most damaging stage; up to 1.5 long In outer wood in spring following overwintering Emerge when black locust blooms; size up to 0.5

13 Hosts of EAB in its Native Range EAB is not a very serious pest in its native range because trees there have evolved with the pest and developed resistance to EAB. There are also natural enemies of EAB in Asia that help keep EAB populations in check. Manchurian ash (F. mandshurica), Chinese ash (F. chinensis), and Korean ash (F. rhynchophylla) are native hosts for EAB in Asia. Mark Whitmore, Cornell University Herman, D.E., et al North Dakota tree handbook. USDA NRCS ND State Soil Conservation Committee

14 Hosts of EAB in its Introduced Range Because native ash trees in North America did not co-evolve with EAB, these species have not developed resistance to the pest. Even healthy trees are vulnerable to infestation. In North America, EAB is capable of infesting all native ash trees (Fraxinus spp.). Fortunately, it has not been observed infesting any other types of trees. The most common ash trees in the US are: Green ash (F. pennsylvanica) White ash (F. americana) Black ash (F. nigra) Blue ash (F. quadrangulata) Rebecca Hargrave, Cornell Cooperative Extension

15 EAB Host Distribution in the US Ash are an important part of eastern forests, sometimes becoming the dominant species especially in swamp forests and in old fields that are reverting back to forest.

16 Basal Percentage of Ash by County In New York Green ash is an important tree in the wetlands of the Lake Ontario Plain, in some counties representing up to 28% of the Basal Area. White ash is a common upland species in the Southern Tier and is an important timber species.

17 Natural Enemies and Population Control Natural enemies and tree resistance keep native insect populations in check. When EAB was imported to the US it left all the natural enemies behind. However there are a few natural native to the US that have begun to exploit EAB as a food source. EAB larvae are a favorite food of woodpeckers. Infested trees often are riddled with holes and scaled bark from woodpeckers foraging on larvae. Unfortunately, woodpecker feeding is not enough to suppress EAB. David Cappaert, Michigan State University, Bugwood.org

18 Natural Enemies and Population Control A couple native parasitic wasps have discovered EAB (Antanycolus spp. and Spathius spp.) sometimes causing significant levels of mortality. They lay eggs in EAB larvae under the bark. A native predatory wasp, Cerceris fumipennis, has been found to capture EAB as well as other Buprestid beetles to provision the nest that they dig into the ground. They will lay an egg on the beetles and the larvae will consume the prey. David Cappaert, Michigan State University, Bugwood.org Watching Cerceris nests to see what beetle species are being collected is very useful for detection, but the wasp does not kill enough EAB to effectively suppress its population. To learn more about biological control of EAB, visit:

19 Natural Enemies and Population Control Scientists are in the process of implementing Classical Biological Control by searching for natural enemies where EAB is native. Three species look promising and are being released at selected sites in the US: Spathius agrili: parasitizes larvae Tetrastichus planipennis: parasitizes larvae Oobius agrili: parasitizes eggs Debbie Miller, USDA Forest Service, Bugwood.org To learn more about biological control of EAB, visit:

20 Review What trees in North America are commonly infested by EAB? Answer What two things keep populations of native insects in check? Answer Mark Whitmore, Cornell University

21 Module Summary There are four main life stages for EAB: egg, larva, pupa and adult. Adult EAB emerge from trees in spring and early summer. The larval stage is the deadliest to ash trees because larva feed on the tree s phloem and cambium, which disrupts the flow of food and nutrients. In North America, EAB is capable of infesting all plants in the Fraxinus genus. The most common Fraxinus species include white, green, blue and black ash. Natural enemies to EAB include woodpeckers and certain native, as well as, imported stingless wasps. These enemies have not been found to appreciably suppress EAB populations in North America but work continues.

22 Credits Content adapted from the NPDN EAB modules prepared at Virginia Tech; published June 2010 Mark Whitmore, Forest Entomologist with Cornell University Department of Natural Resources, Prepared by Rachel McCarthy, NEPDN Education and Training Coordinator, Department of Plant Pathology and Plant-Microbe Biology, Cornell University,